Light weight racing wheel

ABSTRACT

A wheel having spoke members connecting the hub portion with the rim portion that are hollow and connect with the hub portion in a sealing relationship. The opposite ends of each of the hollow spoke members thereby exposing the inside of each of the spokes. A hole is located in one of the spokes near the hub for inflating a tire mounted on the rim portion.

United States Patent 11 1 1111 3,779,61 1

Phillippe Dec. 18, 1973 LIGHT WEIGHT RACING WHEEL 1,558,656 /1925Waterbor 301/ l,506,098 8/1924 W'de Inventor 1 1??? 'g' Hetherse":3,253,862 5/1966 Witanabe 1301/65 0 o ng an [73] Assignee: Velts FordSales Co., Torrance, Primary Examiner Richard J Johnson Attorney-GeraldSinger [22] Filed: Apr. 12, 1972 [2]] Appl. No.: 243,232 57 ABSTRACT Awheel having spoke members connecting the hub 2? 'Jg portion with therim portion that are hollow and con- I I nect with the hub portion in asealing relationship. [58] Field of Search 301/65, 64 SH, 79, Th d f h fth h H k ,301/63 152/8 9 l0 6 e opposite en s o eac o e o ow spo emembers thereby exposing the inside of each of the spokes. 56 R f d Ahole is located in one of the spokes near the hub for UNITE; 5:235: 8LiTENTS inflating a tire mounted on the rim portion.

3,656,53! 4/1972 Ross 301/63 PW 6 Claims, 4 Drawing Figures ff y? 1/,

LIGHT WEIGHT RACING WHEEL This invention relates to a high speed racingwheel and more particularly to a hollow spoked wheel of improved design.

In an effort to improve the performance of the modern high speed vehicleand more particularly the racing car, it is desirable to make the wheelas light as possible. The modern racing wheel has therefore beenconstructed of such materials as aluminum or magnesium in an effort todecrease the weight of the wheel to thereby increase the sprung tounsprung ratio of the vehicle to the wheel.

Unfortunately, simply making the wheel lighter according to presentdesigns has resulted in wheels that have become unstable and unsafe dueto the lack of ridigity and stiffness in the wheel structure.

It is well known that the wheel or any vehicle must transmit theacceleration torque from the engine to the tire located on therim of thewheels. The spokes connecting the rim with the hub portion of the wheelmust be strong and stiff in the proper direction to withstand anybending caused by the application of torque at the hub of the wheel.Deceleration or braking of the vehicle also produces a bending of thespoke members and in the same plane as the application of theaccelerating torque. The bending moment however is in theoppositedirection since the tire located on the rim of the wheel isapplying a decelerating torque to the hub portion of the wheel throughthe supporting spoke members.

Orthogonal bending forces are also generated across the spokesconnecting the hub portion with the rim portion when the vehicle is in acornering mode or in a turnii'ig operation. Cornering of the vehiclegenerates side forces on the wheel that tends to bend the wheel around adiameter through the hub member.

The spoke members must therefore be rigid and stable with a high momentof inertia in orthogonal directions to resist the bending forcesgenerated by the cornering of the vehicle and the bending forcesgenerated by the application of acceleration and deceleration forces.

Unfortunately, simply making the spoke members thicker in bothdirections to resist the orthogonal bending forces created additionalproblems due to the high rate of expansion of the aluminum and magnesiumof which the wheels are presently being constructed. As is well known inthe casting art, connecting a thick walled member with a relatively thinwalled member creates cooling problems and interdendritic porosityproblems due to the large volume change in the metal from the moltenstate to the solid state. These porosity problems exist whether thewheel is being cast by means of the conventional sand casting techniquesor by injected molding techniques. The cooling process causes a verylarge change in the volume of the metal. In the area connecting a thinwalled section with a relatively thick walled section, the outsideportion cools first and contracts, leaving the inside portion which isstill warm in an expanded state to draw away from the outside sectionthereby causing holes and areas of porosity generally identified asinterdendritic porosity. These openings or holes have the effect ofmaking the structure weak since the density of the metal is not constantbut changes throughout the cross sectional area of the wheel.

The hub must of necessity have a thickness sufficient to transmit thetorque of the enginewhen it is accelerating and to also transmit thetorque of the engine when it is accelerating and to also transmit thedecelerating torque when the car is being braked. In addition, the hubmust have the necessary thickness to support the bending forcesgenerated when the car is drifting through a turn. Hence, the thicknessof the hub is usually determined by external forces on the wheel and asa result, a certainthickness of magnesium or aluminum is necessary towithstand the forces generated.

In view of the present day trend towards tires having a wide tread whichmay vary from a tread of 10 inches from bead to bead to a tread of 20inches bead to head it is recognized that the rim of the wheelsupporting the tire represents a substantially large cross sectionalarea of metal since the average diameter of the wheel may vary fromapproximately 12 to 16 inches. In order to reduce the weight of thewheel to a minimum it is necessary therefore that the thickness of therim be made as thin aspossible consistent with the loads transmitted bythe'tires to the hub portion. Connecting relatively the thin rim to thethick spoke members causes the porosity problems mentioned above.

In accordance with the present invention, four orthogonally locatedhollow spoke members are used to interconnect the hub portion with therim portion of the wheel. Each spoke is connected to the hub in a sealedrelationship. A suitable fillet is used at each juncture between theradiating hollow spoke members and the hub portion. The walled thicknessof the spoke is chosen so that the thickness of the spoke members plusthe thickness of the fillets together approximate the thickness of thehub member at the point of connection. In this fashion theinterdendritic porosity problems are minimized at the junction of theindividual spoke members to the hub members.

In the preferred embodiment, the spoke members are tapered radially tothe rim portion where each of the spoke members terminates in an openannulus on the face of the rim member. Due to the open annulus there isno need for fillets or other devices which increase the thickness of theattaching walled members of the spokes to the walled thickness of therim. As a result of this construction, the thickness of the wallledspoke members terminating in the rim member is substantially the samethickness as the rim member and hence, the interdendritic porosityproblems in this area are also substantially eliminated.

The tire is mounted on the rim member in the conventional manner. Avalve stem for inserting air into the tire is located in one of thespokes near the hub member since each of the spokes is hollow andcommunicates through the annular opening with the internal pressurelocated within the tire. Locating the stem in one of the spoke membersclose to the hub portion of the wheel reduces the unbalancing effectcaused by the stem to a minimum. In the usual situation the stern causesan unbalanced situation since it is located on the rim member at amaximum distance from the hub 7 member.

minates in the rim as a triangle which has the maximum stiffness for agiven shape.

Further objects and advantages of the present invention will be mademore apparent by referring now to the accompanying drawings wherein:

FIG. 1 is a side view of the wheel constructed according to theprinciples of the present invention;

FIG. 2 is a cross section along lines 22 of the wheel illustrated inFIG. 1;

FIG. 3 is a cross section of the wheel illustrated in FIG. 1 along lines33; and

FIG. 4 is a cross section of the wheel illustrated in FIG. 3 along lines4-4.

Referring now to FIG. 1 there is shown a wheel constructed according tothe principles of the present invention. Located about the central axisis a hub portion 12 that is connected to the axle by means of a singlelocking nut (not illustrated). Radiating from the hub 12 are fourequally spaced hollow spokes 14, 16, 18, and 20. A rim member 22circular in form and attached to each of the spokes 14, 16, 18, and 20,is adapted to hold a tire in the conventional manner.

The external shape of each of the hollow spokes 14, 16, 18, andapproximates a truncated triangle with the truncated or small portion 24located in the front of the wheel defined as that portion of the wheelthat is visible when installed on the car. The base portion 26 of eachof the hollow spokes is in the rear of the wheel and is substantiallylarger than the front portion 24 in the approximate ratio of 3 to 1.

The external triangular shaped spoke has certain inherent advantagessince the changing volume of the openings between the spokes changesfrom a maximum 28 at the front of the wheel to a minimum opening 30 atthe rear of the wheel. This changing volume produces a venturi effectthat enhances the flow of air through the openings which is mostdesirable for cooling brakes and other related equipment when thevehicle is in motion. In addition the truncated side 24 on each of thehollow spokes 14, 16 18 and 20 acts as the leading edge of a plane forforcing air through the variable shaped opening between the spokes.

The truncated shaped spokes 14, 16, 18, and 20, also lend themselves tobeing readily cast in the conventional sand casting technique since thevariations in width from the truncated frontal portion 24 to the rearbase portion 26 provides a convenient draft angle that is considered sonecessary when sand casting.

All the spokes are identical except that one spoke 14 contains anopening 32 for accepting a valve tire stem for applying air to the tirelocated on the rim of the wheel. All of the spokes 14, l6, l8, and 20are sealed to the hub member 12 and open to the rim member 22. It can beappreciated therefore that inserting air through a valve stem insertedinto the hole 32 will therefore allow the air pressure to communicatewith the inside of the tire located upon the rim 22. Bringing the valvestem closer to the hub member 12 reduces any unbalancing tendenciescaused by the weight of the valve stem assembly.

Referring now to FIG. 2 there is shown a cross section of spoke 14 alonglines 22 of FIG. 1 which more fully illustrates the internal dimensionsof the hollow spoke 14 as an equalateral triangle having substantiallyequal interior sides 36, 38 and 40. The triangular shape provides alarge moment of inertia about the neutral axis passing perpendicularthrough the central axis of rotation of the wheel and a high moment ofinertia about a neutral axis that is perpendicular to the first neutralaxis so as to provide strength to resist bending when the car iscornering as well as when the car is accelerating or decelerating. Thetriangular shape also provides an additional measure of stiffness sincethe lower end of each spoke is attached to the hub member 12 in a sealedrelationship. In addition the rim end of each spoke is terminated in anopen annulus having the general shape of a triangle on the face of therim member 22. The triangular opening on the rim member provides anincreased stiffness at the points of attachment between the individualspoke and the rim member itself.

Referring now to FIG. 3, there is shown a cross section of the wheelillustrated in FIG. 1 taken along lines 33 of FIG. 1. The section lines33 pass through spoke 24 and makes a 45 angle through the openingbetween spoke l8 and 20 in order to more fully illustrate the hollowspoke 24 and the back of the hub 12 which contains four equally spacedholes 42 for accepting driving lugs connected to the driving flange onthe axle of the vehicle.

The cross section of the hollow spoke 18 illustrates the forward wall 14and the rear wall 26 and the general tapering of both walls from amaximum at the hub member 12 to a minimum at the rim member 22. Theattachment of the front wall 14 to the hub member 12 includes a radius44 defining a fillet that has the effect of increasing the wallthickness of member 14 that is actually in contact with the hub member12 to approximately the same thickness as the hub member itself. Inother words the walled thickness of outside wall 14 plus the thicknessof the fillet at 44 approximates the thickness of the hub member 12thereby reducing the problems of interdendritic porosity. A review ofrear wall 26 will show that an inside fillet 46 and an outside fillet 48at the point of connecting the wall thickness of the rear wall 16 to thehub member 12. As described in connection with the front wall member 14the combination of the wall thickness plus the fillet at 46 and thefillet at 48 approximates the thickness of the hub member 12 at thepoint of connecting the rear wall 26 to the hub member 12 thereby againreducing the interdendritic porosity problems.

The tapering of the front wall member 14 and the rear wall member 26continues to the point of junction with the rim member 22. This taperingallows a general decrease in width in the front wall member 14 and therear wall member 26. The actual juncture between the front wall 14 withthe rim 22 and the rear wall 26 with the rim 22 takes place with thethickness of the wall members being approximately the same as thethickness of the terminating rim member 22 thereby reducing the problemsassociated with interdendritic porosity. The tapering of the front wallmembers 14 and the rear wall member 26 also aids the sand castingmanufacturing technique since a natural draft angle is produced by thetapering of the wall members.

The rim member 22 contains a flange 50 at the forward end and a flange52 at the rear portion in order to properly hold and contain the tire.The rim 22 contains a general circular depression 54 where theindividual spokes terminate and connect to the rim. The actual shape andcurvature is a function of the load to be carried by the wheel and theneed for stress distribution within the wheel itself under the varyingloads to be encountered.

Referring now to FIG. 4 there is shown a section taken along lines 44 ofFlG. 3 which more fully illustrates how the individual spoke is closedat the hub portion 12 and is terminated in an open annulus at the rimmember 22. FIG. 4 more fully illustrates how the individual fillets 56and 58 combine with the thickness of the wall member to thereby providea thickness of metal that is approximately equal to the thickness ofmetal of the hub member 12. The terminating of the wall members of thehollow spokes is also more fully shown in the terminating area betweenthe wall members and the rim member 22. It will be noted that since thehollow spoke is opened in the face of the rim member 22 that additionalfillets are not needed and hence, the tapered thickness of the wallmember of the spokes can be made approximately equal to the thickness ofthe rim member 22, and in this way substantially eliminate theinterdendritic porosity problems associated with prior art devices.

The expanding opening of the hollow spoke to the outside rim area alsoimproves the sand casting technique of manufacture of the defined wheel.Trapped gasses that may have a tendency to accumulate now have anopportunity to be moved and propelled from the restricted opening nearthe hub 12 to the expanded opening in the area of the rim 22. Anytendency for gasses to be trapped with resulting blow holes is minimizedby the natural draft angle of the wall members themselves and thedefined opening of each spoke in the rim member.

What is claimed is:

l. A light weight racing wheel comprising:

a thick walled hub member adapted to be connected to an axle,

a thinned walled annular rim member adapted to hold a tire, and

a plurality of hollow spokes having tapered wall members each connectedin a sealing relationship to said hub member at one end and terminatedin an open annulus on the face of said rim at the other end,

said tapered wall members having a thick end mating with said thickwalled hub members and a thin end mating with said thin walled annularrim members.

2. A wheel according to claim 1 in which the walled thickness of each ofsaid spokes contacting said hub is substantially the same thickness assaid hub.

3. A wheel according to claim 1 in which the walled thickness of each ofsaid spokes contacting the rim is substantially the same thickness assaid rim.

4. A wheel according to claim 1 which includes four hollow spokes eachhaving an interior triangular shape.

5. A wheel according to claim 1 in which the external shape of eachspoke is a truncated triangle of constant outside dimensions in whichthe smaller end is in front and the larger end is in the rear of thewheel.

6. A wheel according to claim 1 which includes a hole in one of saidhollow spokes for accepting a valve stem for inserting air in a tiremounted on the rim.

1. A light weight racing wheel comprising: a thick walled hub memberadapted to be connected to an axle, a thinned walled annular rim memberadapted to hold a tire, and a plurality of hollow spokes having taperedwall members each connected in a sealing relationship to said hub memberat one end and terminated in an open annulus on the face of said rim atthe other end, said tapered wall members having a thick end mating withsaid thick walled hub members and a thin end mating with said thinwalled annular rim members.
 2. A wheel according to claim 1 in which thewalled thickness of each of said spokes contacting said hub issubstantially the same thickness as said hub.
 3. A wheel according toclaim 1 in which the walled thickness of each of said spokes contactingthe rim is substantially the same thickness as said rim.
 4. A wheelaccording to claim 1 which includes four hollow spokes each having aninterior triangular shape.
 5. A wheel according to claim 1 in which theexternal shape of each spoke is a truncated triangle of constant outsidedimensions in which the smaller end is in front and the larger end is inthe rear of the wheel.
 6. A wheel according to claim 1 which includes ahole in one of said hollow spokes for accepting a valve stem forinserting air in a tire mounted on the rim.